For measuring inductance L, static capacitance C and resistance R between two terminals of a semiconductor device or L, C, R of a single electric element, a pinch-type connecting terminal or a test clip has been frequently utilized. The test clip is connected to a measuring apparatus via lead wire and clips onto a lead section, a pin or the like of the DUT, (hereinafter referred to as "lead section to be measured").
FIG. 1 shows a test clip which has been conventionally used in general measurements. This test clip includes an electroconductive pin 2 which is slidably inserted into the insulating housing 1 and the hook-shaped terminal section 3 at a tip of the electroconductive pin 2 which can be retractably movable in and out of the tip of the insulating housing 1. The electroconductive pin 2 is urged by a spring in such a direction that the hook-shaped terminal section 3 is retracted towards one end of the insulating housing 1. The electroconductive pin 2 is ultimately connected to a measuring apparatus (not shown) via the lead wire 5, which is disposed in the pusher 4. The pusher 4 is located at one end of the electroconductive pin 2.
The hook-shaped terminal section 3 of the test clip can be moved away from the insulating housing 1 by pushing the pusher 4 toward insulating housing 1, and the hook-shaped terminal section 3 then engages a lead section to be measured 6 of the DUT. Accordingly, when the pusher 4 is released, the lead section to be measured 6 is urged by hook-shaped terminal section 3 and a tip of insulating housing 1.
FIG. 2 shows an application of the conventional test clip of FIG. 1 to which the LCR measuring apparatus is connected for measuring selected impedance of the DUT 31 through the Kelvin (four-terminal) connection. The Kelvin configuration for an impedance measurement has been understood by those skilled in the art. A comparison of various configurations for such an impedance measurement is, for instance, described in "The Impedance Measurement Handbook" published in May 1989 by Hewlett-Packard company p. 3-1, 3-3.
Since it is necessary to connect a current supply terminal and a voltage measurement terminal of the LCR measuring apparatus 9 with two lead sections 6 of the DUT 31, two test clips shown in FIG. 1 are required for each lead section 6. Thus, a total of 4 test clips must be utilized.
In FIG. 2, a.sub.1i and a.sub.2i are connection points for supplying current from the LCR measuring apparatus 9 to the DUT 31. a.sub.1v and a.sub.2v are connection points for measuring a voltage across the DUT 31 in response to the supplied current to obtain impedance of the DUT 31. Since four test clips are used for connecting these points, lead wires between a.sub.1v and a.sub.1i or a.sub.2v and a.sub.2i provide an additional resistance to such voltage measurements. This will cause an error in voltage measurement of the DUT. Accordingly, such connecting device which allow a more precise voltage measurement at points a.sub.1v and a.sub.2v has been desired. However, certain DUT's may not have enough room for two of such test clips. Even though they could be connected, such arrangement becomes time-consuming and laborious. Further, wiring of four test clips may cause an error in connection.
In order to overcome the above problems, an alligator-type test clip having two terminals 7a and 7b as shown in FIG. 3 has been used. The alligator-type test clip may be utilized in the Kelvin connection respectively by connecting lead wires 8a and 8b to a current and voltage terminal of the LCR measuring apparatus respectively (not shown), and a connecting lead section to be measured 6 to terminals 7a and 7b, which are in turn conductively connected to the lead wires 8a and 8b.
However, in order to keep their rigidity, terminals 7a and 7b must contain an electroconductive plate material of some thickness (for example, approximately 0.8 mm) so as to open the terminals 7a and 7b at a suitable angle. Both tips of the terminals 7a and 7b must be apart at least for a distance of approximately 5 mm for connecting a lead section to be measured 6. Accordingly, when a lead-to lead pitch (i.e. the distance between two lead sections 6 in FIG. 3) is smaller than approximately 5 mm, the size of the above described clip is too large for connection. In addition, this type of test clips may not firmly stay on the lead section to be measured due to their structure.